Many Americans fondly believe it is only diplomatic tact that restrains them from surgical strikes against their enemies in Pakistan to prosecute the “war on terror”. But on the night of June 10th, the bloody complications of such forays became starkly apparent. American-led NATO forces, based in Afghanistan, mistakenly killed at least 11 Pakistani paramilitaries in an airstrike across the border.

The killings took place in the Mohmand area of Pakistan, a no-man's-land, where one country bleeds into the other. It is in a part of Pakistan called the Federally Administered Tribal Areas—a name that is more of an aspiration than a description. The Pakistani army has withdrawn from large parts of the area, leaving lonely border posts manned by paramilitaries called the Frontier Corps.

The trouble started when the Afghan National Army tried to set up a border post in Mohmand. They were dissuaded by the Mohmand Rifles, a detachment of the Frontier Corps. As the Afghan forces retreated, they came under attack from the Taliban. The NATO airstrikes they called in failed to distinguish between the Taliban and the Mohmand Rifles, who wear the same garb, a salwar kameez, as their militant rivals. The final death toll is not yet known. A number of riflemen are missing.

The Frontier Corps and the Taliban share more than a dress code. They belong to the same Pushtun ethnic group, which populates both sides of the border, and their distaste for the Americans differs only in degree, not kind. The killing of their comrades will sow further disaffection. It was not the first time American-led NATO forces have fired missiles across the border, but it was the first time so many Pakistanis had been killed.

The Americans were quick to defend the strike as a legitimate act of self-defence. They have released a video to bolster their case. But Pakistan's prime minister denounced the attack as an affront to the country's “sovereignty, dignity and self-respect”. It “hit at the very basis of co-operation and sacrifice with which Pakistani soldiers are supporting the coalition in the war against terror”, a military spokesman said, denouncing the act as “absolutely unprovoked and cowardly”.

Co-operation is anyway not what it was. Since President Pervez Musharraf was sidelined by Pakistan's February elections, the Americans do not know whom to call on to help orchestrate their fight in these nettlesome border regions. The Pakistani army, which always had mixed feelings about pummelling their erstwhile Taliban allies, has been only too happy for the civilian politicians in the new government to carry the can for the war on terror. But that government, an unsteady coalition, is itself unsure of how to proceed. It must square the demands of Pakistan's regional governments, the army, the Americans and its own voters.

In the borderlands, a rough-and-ready pragmatism reigns. The Frontier Corps will strike local truces with the Taliban, which may or may not leave the militants free to attack other targets. Unsurprisingly, the corpsmen are more interested in staying alive than prosecuting America's war aims. Sadly for the men of the Mohmand Rifles, such on-the-ground diplomacy offers little protection from the air.